663
FXUS65 KPSR 042045
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
145 PM MST Sat May 4 2024

.SYNOPSIS...
Slightly above normal temperatures will continue today,
before a dry weather system passing to our north ushers in cooler
temperatures by Sunday. This weather system will lead to breezy
to windy conditions today across southeast California and across
the majority of the area on Sunday. Heading into next week,
temperatures will slowly rebound while remaining seasonably dry.

&&

.DISCUSSION...
Latest water vapor satellite imagery shows a very potent upper-level
low pressure system just off the Oregon coast as of this morning.
This system during the next 24-30 hours will move through the
Great Basin and Intermountain West. Out ahead, temperatures today
will continue to run a few degrees above normal with highs across
the lower deserts topping out in the low to locally mid 90s. As
the low pressure system moves inland later today, a tightening
pressure gradient will lead to strong gusty winds later this
afternoon and evening across portions of southeast California. The
strongest winds are expected across Imperial County, where gusts
in excess 40 mph are likely and where a Wind Advisory is in
effect. The strong gusty winds can lead to areas of blowing dust,
resulting in temporary reductions in visibilities.

Heading into Sunday, as the low pressure system moves through the
Great Basin and Intermountain West, the pressure gradient will
tighten across the entire area leading to widespread breezy to
windy conditions. Widespread afternoon and early evening gusts
upwards of 30-35 mph are likely across the Arizona lower deserts
while locally higher winds in excess of 40-45 mph are likely
across portions of southeast California and the higher terrain to
the north and east of Phoenix. Along with the gusty winds, cooler
temperatures are expected with highs only topping out in the upper
70s to low 80s across the western deserts while the south-central
Arizona lower deserts will see higher temperatures in the mid
80s.

The weather pattern through a good portion of next week will feature
a general large trough extending from the Plains through the
Pacific Northwest with the southern fringe setting up across the
Desert Southwest. As a result, a mostly zonal flow will set up
over the region with temperatures gradually rebounding into the
low 90s across the lower deserts heading through the middle of
next week. Heading into the end of next week through next weekend,
as the troughing pattern dissipates, a ridging pattern is being
hinted by the ensembles in building in from the west. This would
result in temperatures rising a bit more, potentially into the mid
to upper 90s across the lower deserts with a 20-30% chance of
approaching 100 degrees.

&&

.AVIATION...Updated at 1759Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Light winds will persist through the remainder of the morning before
veering toward the west this afternoon with some afternoon breezes
gusting upwards of 15-20 kts. Westerly winds will weaken this
evening but will persist into the overnight hours before making a
shift to the southeast after midnight. West to southwest winds
then resume Sunday morning around 16Z with speeds increasing. FEW-
SCT high clouds around 20 kft will pass over the region throughout
the period with lower bases to around 10 kft expected Sunday
afternoon as a cold front pushes through south-central Arizona.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will be the primary aviation weather concern through the TAF
period. Strong westerly winds at KIPL and southwesterly winds at
KBLH will increase through the afternoon and evening. Winds will be
strongest at KIPL where gusts this afternoon will climb upwards
of 25-35 kts with gusts expected to exceed 35 kts at times this
evening. Meanwhile at KBLH, winds won`t be as strong but will see
gusts to around 25-30 kts through the evening before weakening.
Strong winds will promote the potential for some lofted blowing
dust, which could lead to surface/slantwise visibility reductions.
Wind speeds will remain elevated through the overnight period
before increasing again Sunday morning as a cold front passes
through the region. Otherwise, expect to see fluctuating coverage
of high clouds throughout the period.

&&

.FIRE WEATHER...
A weather system moving just to the north this weekend will bring
breezy to windy conditions focused more during the afternoon and
evening hours along with cooler conditions starting Sunday. Wind
gusts above 30 mph are likely later today across much of the
western districts and then areawide on Sunday. The strong winds
and dry conditions will lead to elevated fire weather conditions
over much of the area this weekend. Min RHs through the weekend
will be around 10-20%, while overnight Max RHs will be around
30-60% for most areas. For next week, weak high pressure will
remain over the region allowing for temperatures returning to
slightly above normal, while seasonably dry conditions persist
with MinRHs dropping to around 10%. Lighter winds are expected
into next week, but some afternoon breeziness can be expected
each day.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 9 AM PDT Sunday for CAZ560.

     Wind Advisory until 8 PM PDT Sunday for CAZ563>567.

     Wind Advisory until 11 PM PDT Sunday for CAZ562.

&&

$$

DISCUSSION...Lojero
AVIATION...Smith
FIRE WEATHER...Lojero/Kuhlman